Leitmotif
Leitmotif (līt"mo*tef") , noun
[German, leading motive.]
1.
(Music) a guiding theme; in Wagnerian opera, a marked melodic phrase or short musical passage which always accompanies the reappearance of a certain person, situation, abstract idea, or allusion in the course of the play; a sort of musical label. Also called Leading motive.
2.
a recurring theme in the activities of a person or group.
Also: Leitmotiv